Vehicle rearview mirrors of the so-called “flipper mirror” type include an actuation mechanism driven by an external lever to move the mirror surface between night and day modes that use different features of the mirror to reflect light at different levels. These actuation mechanisms are configured to be stable in both such positions and otherwise to be urged toward the closest of the stable positions. Known rearview mirror toggle mechanisms may be susceptible to inadvertent actuation, particularly when in the night position, wherein the mirror substrate is angled upwardly toward the vehicle headliner. Such inadvertent actuation may be caused by a user adjusting the position of the substrate by grasping and moving the mirror housing, intending to move the housing relative to an associated mounting structure. During such movement, particular forces can urge the housing toward the opposite stable position with respect to the mounting structure, which may cause such inadvertent actuation of the actuation mechanism and corresponding movement of the housing and, accordingly, the substrate into the opposite stable position. In the case of a standard prism mirror, such inadvertent actuation may be inconvenient.